How to check for bad RAM modules in your PC

Stop mysterious crashes and system errors

By Marvin Tobisch | PC Advisor | 28 February 13

If you have become the victim of unprovoked bluescreens and frequent system crashes as of lately, you might want to have a look at the RAM in your PC or laptop. We'll show you how you can thoroughly test it with specialised tools.

Apart from the ultimate piece of IT troubleshooting advice "Have you tried turning it off and on again?", few other methods are quite as successful at resolving inexplicable PC issues as checking for a broken RAM module. This particularly applies to PCs with telltale signs like constant bluescreens of death (BSoD), distorted graphics in 3D games and failed booting attempts, often in the company of strange beeping sounds. Though most of these symptoms can have a wide range of other causes, checking the RAM first usually saves you a lot of time and effort – after all, hardly any other hardware component is so infamously known for its baffling proneness to cause seemingly random problems. See also:Speed up your PC with a RAM disk

To check your memory for defects, we recommend two complementary methods: The quick and easy-to-use Memory Diagnostics Tool from Microsoft included in Windows Vista, 7 and 8 and the more sophisticated and in-depth Memtest86, which has been around for 20 years and is often considered to be the best free memory testing tool available. Which one of them you want to use is ultimately up to your own preferences and spare time, but letting both have their take on the situation certainly won't hurt the diagnosis either.

Testing with the Memory Diagnostics Tool

The Windows Memory Diagnostics Tool is one of the better and more convenient memory tests out there. Plus, it's already included in your basic Windows package, so you can start it right away and don't need to bother with installing third party software. Keep in mind though, that the memory test itself is run independently from Windows in order to minimize memory load, so that you will need to reboot your PC in the process.

To get started, hold down the Windows-key + R to open up the Run prompt. Type "mdsched" in the empty field and hit Enter. After doing so, a new window will pop up, asking you to restart your PC. Do so and wait for the Windows Memory Diagnostics Tool to load. By default, the tool will now start the standard scanning process automatically, though advanced user might want to have a look at the options menu by pressing F1 before that. Depending on your CPU performance and memory size, the scan might take a little while to complete.

After finishing, the tool will automatically restart your PC and throw you back into the normal Windows interface. Search the bottom right area of your taskbar for an overview of the testing results with all relevant information. If errors have indeed been found, the tool will attempt to pin-point their origin and walk you through solving the problem. In the most unfortunate case, you may have to swap the faulty module out.

Testing with Memtest86

In comparison to the Windows Memory Diagnostics Tool, Memtest86 is often regarded as the more thorough solution. As a drawback, it also requires slightly more preparation to utilize: Memtest86 comes in the form of an ISO-Image, so that you will have to burn it on a disk with another program (such as ImgBurn or Hiro Burner) before being able to use it. In addition, you might need to have a look into your BIOS settings first to ensure that your boot order prioritizes your disk drive in favour of your hard drive, thus making sure Memtest86 won't simply get skipped while booting.

If everything is in order and ready to go, restart you PC with the bootable disk to launch Memtest86. Once inside the main menu, press 1 and Enter to load the latest runtime version. The testing procedure itself will begin automatically after a couple of seconds and go through eleven dedicated routines, testing your RAM's ability to save data discretely as well as safely. Unsurprisingly, this might take some minutes to complete and can be fairly confusing to watch, so don't worry about that.

If all tests have completed processing without complications, your memory modules seem to be fine and the problem lies probably elsewhere. If there have been errors, swap out your RAM modules to find out which one is causing the problem and try plugging it into a different slot. If the issue persists, the module is likely faulty and will need to be replaced.

Tip: If you are interested in modifying the settings of Memtest, pay a visit to the developers website to find out what the various options do and check the forums for possible solutions to problems.